Many marinas, instead of mooring boats, offer the service for their customers of dry land storage. In such facilities, a customer phones ahead to the marina when the customer desires to use the boat and the marina will then remove the boat from storage in a timely fashion, so that the customer does not have to wait for the boat to be put into the water. In many such marinas, space is at a premium and the greater the number of boats that may be stored in a particular facility, the greater the cost efficiency to the owner of the marina. Thus, the pressure is to increase the density of the dry land storage facilities. One limiting factor in the storage facility density is the size of the access lanes which must be provided to enable parking and removal of a boat from a storage slot. Conventional boat trailers and conventional propulsion devices for those trailers, such as trucks or other conventionally steered vehicles, require considerable access room in order to position a conventional trailer For boats other than very small boats, removing a boat trailer manually is not a viable option.
Consequently, there is a need in the marina service industry for a fully-articulated combination trailer and motorized tug which, because of its maneouverability, requires a decreased access lane size to insert or remove a boat carried thereon into a dry land storage slot
Additionally, if the trailer is also selectively elevatable, then, once the boat is positioned in the storage slot, the boat may be elevated and static stands placed beneath the hull so that the articulated trailer may be removed. It is one of the objects of the present invention to provide such a device.
Applicant is aware of U.S. Pat. No. 5,570,754 which issued Nov. 5, 1996, to Stimson for a Tractor and Trailer for Moving Loads in Confined Spaces. Stimson discloses independently-steerable wheels on the tractor. Applicant is also aware of U.S. Pat. No. 3,539,065 for a Trailer and U.S. Pat. No. 4,915,577 for a Self-propelled Mobile Cradle for Boats which teaches a trailer independently elevatable at its rear wheels. Applicant is also aware of U.S. Pat. No. 4,946,182 for a Multi-directional Adjustable Towing Hitch which discloses an trailer hitch articulated joint with two degrees of freedom.